Page 197 - A Mind For Numbers: How to Excel at Math and Science

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avoiding overconfidence

The Power of Teamwork

red had a problem. He couldn’t move his left hand. This wasn’t surprising.
F While singing in the shower, Fred had suffered a nearly lethal right-
hemisphere ischemic stroke a month before. The brain’s right hemisphere
controls the left side of the body, which was why Fred’s left hand was now
lifeless.

Fred’s real problem, though, was worse. Even though he couldn’t move his
left hand, Fred insisted—and truly believed—that he could. Sometimes he would
excuse the lack of motion by saying he was just too tired to lift a finger. Or he’d
insist that his left hand had moved. It was just that people hadn’t been watching.
Fred would even covertly move his left hand with his right, and then loudly

proclaim that his hand had moved on its own.
Fortunately, as the months went by, Fred’s left hand gradually regained its
function. Fred laughed with his doctor about how he’d tricked himself into
believing that he could move his hand in the weeks immediately following the
stroke; he spoke cheerfully about returning to his work as an accountant.
But there were signs that Fred wasn’t returning to business as usual. He used
to be a caring, considerate guy, but the new Fred was dogmatic and self-

righteous.
There were other changes. Fred used to be a keen practical joker, but now he
just nodded along without understanding the punch lines to others’ jokes. Fred’s
skill at investing also evaporated, and his cautiousness was replaced by naive
optimism and overconfidence.
Even worse, Fred seemed to have become emotionally tone-deaf. He tried to

sell his wife’s car without asking her permission and was surprised when she